Margaret Daffodil Graham tries to live a healthy life, particularly since she has a health issue that requires constant attention. Like more than 100 million other Americans, the 74-year-old from Winston-Salem, N.C., has high blood pressure, and she has been taking medication to control it since she was in her 30s. So when she read that her nearby hospital, Wake Forest Baptist Medical Center, was looking for people with hypertension to volunteer for a study, she quickly signed up, knowing the doctors would monitor her blood pressure more intensively and hopefully lower her risk of developing heart disease and stroke.
What Graham didn’t realize was that by joining the trial, she wouldn’t just be benefiting her heart. The study, called SPRINT MIND, was designed to test whether aggressively lowering blood pressure would have an effect on people’s risk of cognitive decline, including symptoms of dementia related to Alzheimer’s disease.
Indeed, the trial’s results are now the first solid confirmation that lowering blood pressure reduces the risk of both mild cognitive impairment (MCI), a degree of brain decline that’s considered the gateway to dementia, and probable dementia. It was a revelation to Graham as well as others who volunteered. “It never occurred to me that controlling my blood pressure could protect me from dementia,” says Arthur Lane, 89, another participant in the study. “I think this is wonderful.”
Some 150 million people worldwide are expected to be affected by dementia by 2050. And while there are many ways people can change their behavior to lower their risk of heart disease and cancer–such as eating a healthy diet, exercising and avoiding or stopping smoking–there are few similar steps that have been scientifically proved to reduce the risk of degenerative brain disorders like Alzheimer’s. Genes play a prominent role in determining who will develop the disease, and age is also a major factor–neither of which are under human control.
That’s why Alzheimer’s experts have focused their attention on developing drug treatments for the disease. But these haven’t yielded any success thus far. In fact, in the past year, many major pharmaceutical companies have either stopped research on Alzheimer’s treatments after early studies of their drugs failed to show they were effective or decided to move away from developing treatments for neurodegenerative conditions altogether. “The data are pretty soft on a lot of things,” says Dr. Ronald Petersen, director of the Mayo Clinic Alzheimer’s Disease Research Center, “so that was discouraging for the field and discouraging for the general public.”
That may finally be changing. The study that Graham and Lane joined provides the strongest evidence yet that there may be something in people’s control that lowers their risk of cognitive decline. The results of the trial, which was funded by various agencies in the National Institutes of Health, were presented at the annual meeting of the Alzheimer’s Association in Chicago in July and immediately buoyed the hopes of Alzheimer’s experts. “It’s one of the first real demonstrations of a lifestyle modification having an impact on late-life cognition,” says Petersen, who was not involved in the study.
The SPRINT MIND study involved more than 9,300 elderly people who had had heart problems or were at higher risk of developing heart disease–some because they had high blood pressure, like Graham and Lane. They were randomly told to lower their blood pressure to either less than 120 mm Hg or 140 mm Hg systolic. (Current guidelines, revised in 2017 after the study began, now recommend that most people keep the upper number, or systolic pressure, under 130 mm Hg.) They were tested over an average of three years on various cognitive skills, including memory and processing of new information.
Biologically, it makes sense that blood pressure would affect dementia, says Dr. Jeff Williamson, chief of geriatric medicine at Wake Forest School of Medicine and the leader of the study. He compares having the right blood pressure to maintaining air pressure in a car’s tires–not too high, not too low. “Over time, high blood pressure can damage the walls of very fragile arteries that deliver blood to the brain and other organs,” he says. “And that can produce some of the things we see associated with dementia: inflammation and small strokes.”
After an average of three years, people who lowered their blood pressure to less than 120 mm Hg lowered their risk of developing MCI or probable dementia as measured by the tests by 15%, compared with people who lowered their blood pressure to 140 mm Hg.
“Controlling blood pressure is not only good for the heart but good for the brain,” says Williamson. “This is the first intervention of any kind that has proven in a randomized trial to reduce the risk of mild cognitive impairment.”
While the study only found a reduction in probable dementia, that doesn’t mean blood pressure can’t affect full-blown dementia. Because dementia takes longer to develop than MCI and the study followed people for only a relatively short period of time, more cases of advanced cognitive decline might not have been detected.
Still, it’s the first time that scientists have found something that can lower even MCI risk in a rigorous, randomized trial. “This provides great encouragement for people to say, Yes, make sure your blood pressure is well controlled, because right now, it’s one of the things you can do,” says Williamson. “This opens the door to testing more interventions.”
The trial’s results come on the heels of other evidence that controlling blood pressure may be an important weapon against cognitive decline. Another recent study, published in Neurology by researchers at the Rush Alzheimer’s Disease Center, found that people with higher blood pressure over a long period of time during their later years tended to have more brain lesions, or areas of dead brain tissue where nerve cells had lost their ability to communicate with one another. They also had more tangles of tau protein, another hallmark of Alzheimer’s that tends to appear later in the disease, which the researchers found when they performed autopsies on the participants.
“We wanted to look at actual changes in brain tissue that are affected by blood pressure,” says Dr. Zoe Arvanitakis, a professor of neurological sciences at Rush and one of the study’s authors. “Our results show that we need to do more research on how changes in blood pressure among the elderly relate to changes in cognitive function and dementia.”
That understanding could lead to treating Alzheimer’s as well as other dementias the same way that cancer and some infectious diseases are treated, with an array of therapies. Petersen, the Mayo Clinic researcher, for example, sees the latest blood-pressure study results as a step toward establishing treatments for Alzheimer’s that combine lifestyle changes and medication. With growing evidence that Alzheimer’s is caused by a multitude of factors, he believes treating the disease will likely require more than just effective drugs.
“There is almost certainly going to be combination therapy for Alzheimer’s down the road,” Petersen says. “And lowering blood pressure is part of the picture.”
Critical to making that happen are effective medications, and there are finally some promising drugs for Alzheimer’s that are now being tested. Unlike current drugs for the disease, which address only the symptoms of cognitive decline and not the root causes of Alzheimer’s, these could be the first to actually slow or even reverse the damage to brain nerves that cause memory loss, disorientation and other problems related to thinking skills. While trials of previous candidates have yielded mostly disappointing results, the latest studies on two drugs, BAN2401 and aducanumab, show they may shrink the amount of disease-causing protein plaques in the brain and could even slow the progression of cognitive decline (see sidebar, right).
Until these new drug treatments complete the final phases of testing, the SPRINT MIND study offers more immediate hope for battling dementia.
For Graham, the findings have reinforced her motivation to keep her blood pressure as low as possible. “I can deal with my body failing, but without your mind, there’s nothing,” she says. “So I do what I need to do to keep my body fit and hopefully not lose my mind.”
As part of her efforts, Graham takes long walks, does her own yard work in the summer and makes regular trips to a local YMCA to train with weights to maintain muscle strength. She is grateful that her contribution to the study means that more people may be able to avoid developing MCI or even dementia. “I can leave some type of legacy in this world,” she says.
Lane, who is retired, and his wife Diane are hoping that his participation in the study will inspire their family members to lower their blood pressure–especially their two children who have hypertension. “I guarantee you this will be a discussion that we have with all of our children,” says Diane. Having a way to control their future risk of dementia, she says, “puts the ball back in our court.”